Question

I’ve got an application using sockets (which I did not write, so bear with me) and when I try to close a socket, closesocket() fails with error WSAEOPNOTSUPP and the socket sticks around…as in, it is not fully deleted.

The socket is created as follows:

bool Socket::CreateConnection()
{
   int error;
   struct addrinfo hints;
   struct addrinfo *list = NULL;

   memset(&hints, 0, sizeof(hints));
   hints.ai_family = AF_INET;
   hints.ai_socktype = SOCK_STREAM;
   hints.ai_protocol = IPPROTO_TCP;

   error = getaddrinfo(socketAddress.c_str(), socketPort.c_str(), &hints, &list);
   if (error)
   {
      Log().RecordError("Unable to initialize connection to server", WSAGetLastError(), EventTypeError);
   }

   for (struct addrinfo *ptr = list; ptr != NULL; ptr = ptr->ai_next)
   {
      connection = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
      if (connection == INVALID_SOCKET)
      {
         Log().RecordError("Unable to initialize socket connection", WSAGetLastError(), EventTypeError);
         break;
      }

      error = connect(connection, ptr->ai_addr, (int)ptr->ai_addrlen);
      if (error == SOCKET_ERROR)
      {
         closesocket(connection);
         connection = INVALID_SOCKET;
         continue;
      }
      break;
   }

   freeaddrinfo(list);

   return connection != INVALID_SOCKET;
}

And the destructor for the class:

Socket::~Socket()
{
   int error;

   if (connection != INVALID_SOCKET)
   {
      continueReading = false;

      error = shutdown(connection, SD_SEND);
      if (error != SOCKET_ERROR)
      {
         /* Finish any necessary receives to politely close the socket */
         int length;
         do
         {
            char buffer[1024];
            length = recv(connection, buffer, sizeof(buffer)/sizeof(*buffer), MSG_WAITALL);
         } while (length > 0);
      }
      else
      {
         Log().RecordError("Error shutting down connection to server", WSAGetLastError(), EventTypeError);
      }

      closesocket(connection);  //Fails HERE
      int wsa_err = WSAGetLastError();
      if(wsa_err)
          Log().RecordError("closesocket() error", wsa_err, EventTypeError);
   }

   if (winsockInitialized)
   {
      WSACleanup();
   }
}

Anyone have a clue why this would happen??

Answer 1

You’re not checking the return code on closesocket(), which means that WSAGetLastError() may or may not be related to the closesocket operation.